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A174830
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Odd numbers k such that k^2 is an abundant number.
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5
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105, 315, 495, 525, 585, 735, 945, 1155, 1365, 1485, 1575, 1755, 1785, 1995, 2145, 2205, 2415, 2475, 2625, 2805, 2835, 2925, 3045, 3135, 3255, 3315, 3465, 3675, 3705, 3795, 3885, 4095, 4305, 4455, 4485, 4515, 4725, 4785, 4845, 4935, 5115, 5145, 5265
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OFFSET
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1,1
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COMMENTS
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For any number k, the abundance of k^2 is an odd number.
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LINKS
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FORMULA
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MATHEMATICA
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fQ[n_] := Block[{ds = DivisorSigma[1, n^2] - 2 n^2}, ds > 0 && OddQ@ ds]; Select[ Range[1, 5353, 2], fQ@# &]
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PROG
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(PARI) [2*k-1|k<-[1..6e3\2], sigma((2*k-1)^2, -1)>2] \\ M. F. Hasler, Jan 26 2020
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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